1. Field of the Invention
This invention relates to a process for reforming methanol and more particularly, to a process for cracking methanol in admixture with water by the use of a catalyst comprising at least one metal selected from copper, zinc, chromium and metals of Group VIII and oxides thereof, whereby methanol can be stably cracked over a long period of time to obtain a gaseous mixture containing hydrogen and carbon monoxide.
2. Description of Prior Art
At present, crude oil and petroleums refined from the oil have been used as liquid fuels for use in boilers of power stations and internal combustion engines, gas fuels and starting materials for producing reductive gases. Because of the recent rise in oil prices, methanol prepared from fossil fuels other than crude oil has attracted attention for use as the starting materials.
Methanol is advantageous since it is cracked into a hydrogen-containing gas at temperatures much lower than naphtha so that, waste heat can be utilized as the heat source for the cracking reaction.
For the cracking of methanol, there have been proposed several types of catalysts including catalysts which comprise at least one metal selected from copper, zinc, chromium and metals of Group VIII, and oxides thereof, e.g. catalysts in which platinum group elements such as platinum, or base metals such as copper, nickel, chromium and zinc or oxides thereof are supported on a carrier such as alumina, and catalysts for methanol synthesis which comprise zinc, chromium or copper. The present inventors have already proposed catalysts which have higher low temperature activity than the above known catalysts and suffer little side reactions and which consist of at least one member selected from oxides of copper, zinc and chromium, and nickel oxide supported on or mixed with the at least one member (Japanese Laid-open Patent Application Nos. 57-174138 and 57-174139). Also, we proposed a catalyst in which platinum or palladium is supported on a carrier of alumina covered with basic oxides (Japanese Laid-open Patent Application No. 57-68140).
However, the above catalysts have the problem that when methanol alone is used as the starting material, the catalysts do not have satisfactory low temperature activity and carbon deposits thereon with the result that the life of the catalyst is shortened.